将分析湍流拟序结构中的本征正交分解技术运用到离心压气机无叶扩压器的流动稳定性分析中，并将其与Galerkin投影法相结合建立了无叶扩压器内部流场的降阶模型。使用本征正交分解技术提取无叶扩压器在某来流入口角下非定常流场的主要流动模态，将流动控制方程通过Galerkin方法投影至由有限阶本征正交模态所组成的空间上，得到无叶扩压器流动稳定性降阶模型。计算结果表明：该模型可用于判断不同来流入口角下的扩压器流动稳定性，并将降阶模型的计算结果与流场数值模拟结果和线性稳定性预测结果进行对比，验证了此降阶方法的合理性。

The proper orthogonal decomposition (POD) technique in the analysis of turbulent coherent structure is applied to the flow stability analysis of the centrifugal compressor vaneless diffuser,and the combination of this technique and the Galerkin projection method can establish a reducedorder model of the flow field inside the vaneless diffuser.The main flow modes of the unsteady flow field inside the vaneless diffuser at a certain inflow inlet angle are extracted by the proper orthogonal decomposition technique,and the flow control equations are projected to the space composed of a finite number of proper orthogonal modes by the Galerkin method,then a reducedorder model of the flow stability of the vaneless diffuser is obtained.The calculation results show that the model can judge the flow stability of the diffuser at different inflow inlet angles.The calculation results of the reducedorder model compare with the numerical simulation results of the flow field and the linear stability prediction results to verify the rationality of the reducedorder method.

：TH452